Air cooler



FIG. 1 is a front and top perspective view of an air cooler, showing my new design;

FIG. 2 is a rear and bottom perspective view thereof;

FIG. 3 is a front elevation view thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a left side elevation view thereof;

FIG. 6 is a right side elevation view thereof;

FIG. 7 is a top plan view thereof; and,

FIG. 8 is a bottom plan view thereof.

The broken lines depict portions of the air cooler in which the design is embodied that form no part of the claimed design. 

CLAIM The ornamental design for an air cooler, as shown and described. 